The Article “Enumeration of Illumination on Scanning Modes from Real-Time Spatial Light Modulators”, Li Ge et al., Vol. 7, No. 12, Optics Express, pages 403-416, 2000, discloses to use a phase-only spatial light modulator (SLM) in a Fourier-transform set-up together with fast diffractive optics design algorithms for automatically generating complex and rapidly changing laser illumination patterns in the far-field. The spatial light modulator comprises several pixel elements, wherein each pixel element allows to change the phase of the part of a coherent laser beam which meets the respective pixel element. Thus, a broad laser beam covering the different pixel elements is directed onto the spatial light modulator and the phase of the different parts of the broad laser beam, which meet the respective pixel elements of the spatial light modulator, is modified by the respective pixel element. Each pixel element of the spatial light modulator is separately addressable, thereby allowing to modify the phases of different parts of the broad laser beam differently. After leaving the spatial light modulator, the different parts of the broad laser beam, which comprise now different phases, interfere and generate a light pattern which can be used for illuminating, for example, an object. By modifying the phases of the different parts of the broad laser beam by using the several pixel elements, different light patterns can be generated.
The spatial light modulator is a technically complex system which is bulky and expensive.